Yu’s participation at the World Championships has divided opinion.

Competitors in the championships must be at least 14 years of age but Yu was permitted entry because her times met the association’s ‘A’ standard.

But, while Yu’s ability is not in question, not everyone is convinced she should be allowed to compete on the global stage yet.

The topic was discussed on BBC Radio 5 Live with four-time world champion swimmer Karen Pickering and Olympic bronze medallist Steve Parry offering differing opinions.

“To see a youngster go in the events she is doing is on the one hand astonishing, but it does slightly raise the question of how long has she been training hard?” said Pickering.

“What kind of training is she doing? What is that doing to her physically?

“I worry about what it’s doing physically to a child doing that amount of training at that age. We’ve seen it with gymnasts that are pushed too young and the impact it has on their body long-term.”

Parry, though, said Yu’s participation was “positive” and had echoes of Sharron Davies, who represented Great Britain at the 1976 Olympics at the age of 13.

“It’s a young girl who is 12 years of age and it’s right we are asking questions, but I got spanked by a 15-year-old Michael Phelps in Sydney and he went on to be the greatest swimmer we’ve ever seen,” said Parry.

“You can have youngsters, whether it be Sharron Davies, Yu or Katie Ledecky, but we have got to take care of their mental health and make sure they aren’t being pushed too much physically.

“These young proteges should be celebrated.”